UK's MI5 boss warns of 'intense' terror threat

"That threat is multi-dimensional, evolving rapidly and operating at a scale and pace we've not seen before, " Andrew Parker, the director general of MI5, said during a rare public speech to journalists in London.

The intelligence chief said there has been a "dramatic upshift" in terrorist activity this year, which resulted in the London and Manchester attacks which killed a total of 36 people.

Counterintelligence service of great Britain MI5 now conducts more than 500 investigations of suspected terrorist activity, told reporters on Tuesday the head of the organization, Andrew Parker.

Speaking in central London, he said MI5 and the police had stopped 20 plots in the past four years, including seven since March, and would "continue to find and stop most attacks".

The MI5 chief called on technology companies to work with the government on preventing their social media platforms from being used by extremists for communications that can not be monitored.

Andrew Parker said there was now "more terrorist activity coming at us, more quickly" and that it can also be "harder to detect". Extremists of all ages, gender and backgrounds, united only by the toxic ideology of violent victory that drives them, " said Parker, who has headed MI5 since 2013.